Aspherical Multifocal Intraocular Lens

ABSTRACT

A multifocal intraocular lens has an anterior lens surface which includes a first optic of a first radius and a second optic of a different radius. The posterior surface of the lens include an aspheric surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 13/671,900 filed Nov. 8, 2012, which is incorporated by referenceherein in its entirety.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention is for an intraocular lens that is typically usedas a replacement for the natural lens of the human eye. In the eventthat the natural lens of the human eye is removed, for example duringcataract surgery, an intraocular lens is typically implanted in the lenscapsule as a replacement for the natural lens.

2. Description of Related Art

There are several types of intraocular lenses (IOL) that have beendeveloped. They include aspheric lenses, multifocal lenses andaccommodating lenses. Also improved haptics for securing the lens withinthe lens capsule have been developed. These designs to some extentresult in aberations and create a halo effect or result in reducedcontrast and/or brightness.

BRIEF SUMMARY OF THE INVENTION

The current invention overcomes the drawbacks in the prior art with aunique configuration. The lens of the current invention is formed as anaspheric lens with an added lens surface formed on the posterior portionof the lens. Integral with the lens is a haptic system that securelymounts the lens centrally within the lens capsule and thus minimize any“halo” effect or other aberations.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic view of the human eye.

FIG. 2 is a side view of a conventional intraocular lens.

FIG. 3 is a side view of an intraocular lens according to an embodimentof the invention.

FIG. 4 is a front view of the lens shown in FIG. 2

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 it can be seen that the relevant portions of the eyefor purposes of this invention are as follows. Eye 100 has a naturallens capsule 110 in which the natural lens is located and pupil 113,which is surrounded by iris 116. The area forward of the lens capsule110 is generally referred to as the anterior chamber 112 and the arearearward of the lens capsule 110 is referred to as the posterior chamber132. The lens capsule 110 is held in place by ciliary zonules 133 whichextend between the lens capsule 110 and the ciliary body 118. The space131 between the iris 116 and the ciliary zonules 133 is referred to asthe ciliary sulcus 131. The eye also includes cornea 114, sclera 122,choroaid 124, retina 126, fovea 128 and optic nerve 130.

For cataract surgery, a small incision is normally made at the junctionof cornea 114 and sclera 122 and the natural lens can be removed fromthe lens capsule 110 by phacoemulsification, for example. An intraocularlens (IOL) is then implanted within the lens capsule through the sameinitial incision.

FIG. 2 discloses a conventional aspherical lens 10 which includes acentral lens portion 15 having opposing convex lens surfaces 14 and 13.Suitable haptics 11 and 12 extend outwardly from the lens portion 15 forsecuring the lens within the lens capsule.

FIG. 3 illustrates an embodiment of the invention. Intraocular lens 20has a posterior surface 24 which is aspherical in shape. Posteriorradius of surfaces 29 are of equal value. The anterior surface 51 oflens 20 has a first aspherical lens surface 23 which has a radius equalto radius of surfaces 29 and a second lens surface 27 of a smallerradius, thus forming a higher power lens 26 than that of lens surface23.

The radius of surface 27 is less than that of lens surface 23 so that informing lens 26, a flat surface 28 will be formed on the outer peripheryof the anterior side of the lens as shown in FIGS. 3 and 4. Flat surface28 lies in a plane that is parallel to the longitudinal axis 62 of thelens.

FIG. 4 illustrates the haptics utilized to secure the lens within thelens capsule. The haptics are formed in the manner disclosed in U.S.Pat. No. 6,261,321, the entire contents of which is hereby incorporatedby reference thereto. Upper haptic 21 includes vertical legs 33, 34 andcross member 35 extending between legs 33 and 34. Upper haptic 51 alsoincludes a pair of footplates 31 and 32. Legs 33, 34 and cross member 25circumvent an opening 46. The footplates are preferablylentricular-shaped.

Lower haptic 22 is formed similar to haptic 51 and includes lower legs43, 44 and cross member 45 extending between legs 43 and 44. The legs,cross member 45 and lower lens 26 circumvent opening 47. Lower haptic 52also includes a pair of footplates 41 and 42 of lenticular shape.

Lenses 20 may be formed from a single body of a conventional materialutilized for intraocular lens such as acrylic with twenty-six percentwater. Lens surface 26 can be formed by using a Fast Tool Systemavailable from Ametek Precitech, Inc., located in Keene, N.H. The conicbi-aspheric shape of the lens can be determined according to themethodology described in U.S. Pat. No. 7,350,918, the content of whichis hereby expressly incorporated herein by reference thereto.

The distance optic on the multifocal surface is approximately 50 to 70percent of the optical surface, and the near segment is about 50-30percent of the optic, with the preferred distribution of optic beingabout 60 percent distance are 40 percent for near.

Although the present invention has been described with respect tospecific details, it is not intended that such details should beregarded as limitations on the scope of the invention, except to theextent that they are included in the accompanying claims.

I claim:
 1. An intraocular lens comprising: a posterior surface, whereinthe posterior surface comprises a first portion and a second portion,wherein a radius of the first portion and the second portion are ofequal value; and an anterior surface, wherein the anterior surfacecomprises a first aspherical lens surface which has a radius equal tothe first and second portions.
 2. The intraocular lens of claim 1,wherein the posterior surface is aspherical in shape.
 3. The intraocularlens of claim 1, wherein the anterior surface further comprises a secondlens surface.
 4. The intraocular lens of claim 3, wherein the secondlens surface comprises a radius smaller than the radius of the firstaspherical lens surface.
 5. The intraocular lens of claim 4, wherein thefirst aspherical lens surface in conjunction with the second lenssurface is configured to form a higher power lens than the firstaspherical lens surface.
 6. The intraocular lens of claim 1, furthercomprising a flat surface on an outer periphery of an anterior side ofthe intraocular lens.
 7. The intraocular lens of claim 6, wherein theflat surface is parallel to a longitudinal axis of the intraocular lens.8. The intraocular lens of claim 1, further comprising hapticsconfigured to secure the intraocular lens within a lens capsule.
 9. Theintraocular lens of claim 8, wherein the haptics comprise an upperhaptic and a lower haptic.
 10. The intraocular lens of claim 9, whereinthe upper haptic comprises a pair of footplates, legs, and a crossmember.
 11. The intraocular lens of claim 9, wherein the lower hapticcomprises a pair of footplates, lower legs and a cross member.
 12. Theintraocular lens of claim 1, wherein the intraocular lens is made froman acrylic.
 13. A method comprising: making an incision in an eye;removing a natural lens of the eye; and implanting an intraocular lens,wherein the intraocular lens comprises: a posterior surface, wherein theposterior surface comprises a first portion and a second portion,wherein a radius of the first portion and the second portion are ofequal value; and an anterior surface, wherein the anterior surfacecomprises a first aspherical lens surface which has a radius equal tothe first and second portions.
 14. The method of claim 13, wherein adistance optic on a multifocal surface of the intraocular lens isapproximately 50% to 70% of an optical surface of the intraocular lens.15. The method of claim 14, wherein a near segment is about 50% to 30%of the distance optic.
 16. The method of claim 13, wherein the posteriorsurface is aspherical in shape.
 17. The method of claim 13, wherein theanterior surface further comprises a second lens surface.
 18. The methodof claim 13, wherein the intraocular lens further comprises hapticsconfigured to secure the intraocular lens within a lens capsule.
 19. Themethod of claim 18, wherein the haptics comprise an upper haptic and alower haptic.
 20. The method of claim 13, wherein the intraocular lensis made from an acrylic.